Since the bottom of our hopper is flat, it tends to feed from the front of the hopper where the stoker is, leaving a big pile at the back, it sometime gets really low and creates a big valley and almost goes out, but I think I solved the problem.

I added a angle plate to keep the coal towards the front, we will see how well it works....

Who is the manufacturer of the stove? I like the concept that you've shown. Like they say - "a picture is worth a thousand words". Coal exiting the hopper is forced directly into the feeder tray, due to the angled feed of your modification. The only problem I see is twofold. One - the volume that can be stored in the hopper is reduced by a percentage. Two - coal will get trapped between the sides of the ramp and the flat portions of the bottom of hopper. I'm not sure whether by design that the manufacturer didn't angle all four sides towards the opening, or what the issue(s) may be. Glad to see it works for you so far....

You're only really going to get a few extra pounds into the feeder at best, that's pretty close to the angle rice would take. Basically that's just filling in dead spot replacing what would be coal. Manufacturers probably don't do that for economic reasons, it would require more cuts and bends in the metal for little benefit.

I would say only 1-2 pounds reduction, but seems to work, it keeps it trickling down into the feeder easier. I normally keep it full, but sometimes forget and it almost went one night before the modicification.

You are still going to have coal sitting on the flat spot and never get to the feeder unless you help it by hand.

Yes, more bends and probably more time/money for the manufacturer. the old saying "KISS" - Keep it Simple *****

I always like to tinker and find a better mousetrap and share my ideas.

Did you see my top vent modification (to be connected into the furnance in our new house once we move in) It is the other posting under Koker 160 advice?Keystoker Koker 160 Furnance Advice